The Treaty of Alliance was the 1778 agreement that created a formal alliance between the United States and France.
Signed in Paris on February 6, 1778, the treaty followed the American victory at Saratoga and France’s decision to enter the war openly. It complemented the Treaty of Amity and Commerce, which established commercial relations and recognized the United States as an independent trading partner.
The alliance committed France to support the United States against Britain. It also included provisions concerning American independence and promised that neither ally would make a separate peace with Britain. French military, financial, and naval assistance became central to the American war effort.
The alliance was tested during the Yorktown campaign, when French soldiers and sailors helped surround Cornwallis. The relationship continued until the 1800 Treaty of Mortefontaine ended the alliance and settled disputes left from the Revolutionary era.